Here's a great link posted by "biscuit" that will show you how to do the oil changes on Harleys, mostly softails.
HOW-TO TWIN CAM HARLEY ENGINE OIL CHANGE
Please be aware that the author is suggesting 15/50 Mobil car oil that is not for air cooled engines. Use an oil that is designed for air cooled engines like Mobil 1 V Twin oil 20/50.
Changing Primary oil...
HOW-TO TWIN CAM HARLEY PRIMARY OIL CHANGE
Trans oil change...
HOW-TO TWIN CAM HARLEY GEARBOX OIL CHANGE
HOW-TO TWIN CAM HARLEY ENGINE OIL CHANGE
Please be aware that the author is suggesting 15/50 Mobil car oil that is not for air cooled engines. Use an oil that is designed for air cooled engines like Mobil 1 V Twin oil 20/50.
Changing Primary oil...
HOW-TO TWIN CAM HARLEY PRIMARY OIL CHANGE
Trans oil change...
HOW-TO TWIN CAM HARLEY GEARBOX OIL CHANGE